6&#39; Carbamate esters of zearalanol and its derivatives

ABSTRACT

6&#39; Carbamate esters of zearalanol and its derivatives are used to promote growth in ruminants. The compounds have the structural formula: ##STR1## wherein R 1  and R 2 , which may be the same or different, are H, X, or COX, where X is an alkyl group having from 1-6 carbon atoms; and R is NH-Y, where Y is an alkyl group having from 1-6 carbon atoms or a five-membered or six-membered ring; N(C n  H 2n+1 ) 2 , where n is an integer from 1 to 6; or a five-membered or six-membered heterocyclic ring having one N heteroatom and up to one other heteroatom selected from the group consisting of N, S, and O heteroatoms.

This invention relates generally to Resorcylic Acid Lactone (RAL) derivatives and particularly to 6' carbamate esters of zearalanol and its derivatives which are useful for promoting growth in ruminants.

BACKGROUND OF THE INVENTION

Zearalenone and its derivatives are the basic Resorcylic Acid Lactone (RAL) compounds used as the starting materials for the compounds of the present invention. Zearalenone may be prepared by culturing the zearalenone producing strain of Gibberella zeae as taught in U.S. Pat. No. 3,196,019, incorporated herein by reference. Zearalenone and its ring-opened and other derivatives have been reviewed in the literature. Shipchandler, Heterocycles, 3(6):471-520 (1975) and Hidy et al "Zearalenone and Some Derivatives: Production and Biological Activities", Adv. Appl. Microbiol., 22:59-82 (1977).

Zearalenone has been chemically modified to form numerous derivatives. U.S. Pat. No. 3,239,348, incorporated herein by reference, discloses a method for producing zearalenol from zearalenone by reducing the ketone carbonyl group. U.S. Pat. No. 3,239,345, incorporated herein by reference, discloses a method for producing zearalanol from zearalenone and zearalenol by reducing the ketone carbonyl group and/or the macrocylic ring double bond.

These compounds have generally been used to improve growth performance in ruminants and to reduce the severity of vasomotor symptoms associated with menopause in women. These compounds, however, have often been difficult to administer or to have undesirable side effects. In addition, these compounds have often not been as highly effective for the intended purpose as desirable. There is, therefore, a continuing need for new compounds that can reduce problems with administration, lessen the toxic and other undesirable side effects, and improve upon the efficacy of such compounds. One method for meeting these needs has been to produce various derivatives, particularly ester derivatives or compounds that give a biological response similar to the ester derivatives, of the compounds in an effort to improve the efficacy of the compound and lessen any possible side effects.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide 6' carbamate esters of zearalanol and its derivatives.

It is another object of the present invention to provide a method for promoting growth in ruminants by administering to the ruminants a growth promoting amount of 6' carbamate esters of zearalanol and its derivatives.

It is another object of the present invention to provide a composition containing 6' carbamate esters of zearalanol and its derivatives.

These and other objects are achieved by synthesizing 6' carbamate esters of zearalanol and its derivatives and administering the compounds to ruminants to promote growth. The compounds of the present invention have the structure: ##STR2## wherein R₁ and R₂, which may be the same or different, are H, X, or COX, where X is an alkyl group having from 1-6 carbon atoms; and R is NH--Y, where Y is an alkyl group having from 1-6 carbon atoms or a five-membered or six-membered ring; N(C_(n) H_(2n+1))₂, where n is an integer from 1 to 6; or a five-membered or six-membered heterocyclic ring having one N heteroatom and up to one other heteroatom selected from the group consisting of N, S, and O heteroatoms.

Preferably, R₁ and R₂ are H, CH₃, or COCH₃ ; and R is C₆ H₁₂ N (cyclohexylaminium), N(CH₃)₂, N(C₂ H₅)₂, C₅ H₁₀ N (piperidinium), C₄ H₈ NO (morpholinium), C₄ H₈ NS (thiamorpholinium), or C₄ H₈ N (pyrrolidinium).

Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of the invention.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, 6' carbamate esters of zearalanol and its derivatives are synthesized and used to promote growth in ruminants. The compounds have the following structural formula: ##STR3## wherein R₁ and R₂, which may be the same or different, are H, X, or COX, where X is an alkyl group having from 1-6 carbon atoms; and R is NH--Y, where Y is an alkyl group having from 1-6 carbon atoms or a five-membered or six-membered ring; N(C_(n) H_(2n+1))₂, where n is an integer from 1 to 6; or a five-membered or six-membered heterocyclic ring having one N heteroatom and up to one other heteroatom selected from the group consisting of N, S, and O heteroatoms.

Preferably, R₁ and R₂ are H, CH₃, or COCH₃ ; and R is C₆ H₁₂ N (cyclohexylaminium), N(CH₃)₂, N(C₂ H₅)₂, C₅ H₁₀ N (piperidinium), C₄ H₈ NO (morpholinium), C₄ H₈ NS (thiamorpholinium), or C₄ H₈ N (pyrrolidinium).

The compounds are formed by reacting zearalanol and its derivatives directly with carbamyl chlorides or by reacting carbonate derivatives of zearalanol directly with the appropriate amine; typically an amine having the formula

NH₂ --Y, where Y is an alkyl group having from 1-6 carbon atoms or a five-membered or six-membered ring, HN(C_(n) H_(2n+1))₂, where n is an integer from 1 to 6, and five-membered or six-membered heterocyclic compounds having one N heteroatom and up to one other heteroatom selected from the group consisting of N, S, and O heteroatoms. These compounds include but are not limited to methylamine, ethylamine, cyclohexylamine, piperidine, morpholine, thiamorpholine, and pyrrolidine. Methods for preparing carbonate derivatives of zearalanol useful in the present invention are disclosed in copending U.S. patent application Ser. No. 067,532, incorporated herein by reference.

The amount of compound of the present invention administered may vary depending upon the particular type, maturity, and the size of the ruminant. Generally, the compounds according to the present invention are administered to the ruminant in dosages of from 0.01-0.50 mg/kg of body weight, preferably from 0.1-0.3 mg/kg of body weight.

The compounds of the present invention can be administered as the compound or as a pharmaceutically acceptable salt of the compound, alone, in combination, or in combination with pharmaceutically acceptable carriers, diluents, and vehicles. The carrier can be an antibiotic, other growth promoting agent, an inert carrier, and the like. Most preferably, the compounds of the present invention are mixed with a pharmaceutically acceptable carrier to form a composition which allows for easy dosage preparation and administration.

The compounds of the present invention can be administered to ruminants by any suitable method including orally, by injection, using an implant, and the like. Oral administration includes administering the compounds of the present invention in tablets, suspensions, implants, solutions, emulsions, capsules, powders, syrups, water compositions, boluses, feed compositions, and the like. Injections and implants are preferred because they permit precise control of the timing and dosage levels used for administration, with implants being most preferred. The compounds of the present invention are preferably administered parenterally. Such administration may be by intravenous or intramuscular injection, intraperitoneal injection, or subcutaneous implant.

The compounds according to the present invention can be administered to the ruminant in the form of a slow-release subcutaneous implant which is inserted beneath the skin of the ruminant, preferably in the ear for large animals. The implant can take the form of a pellet which slowly dissolves after being implanted in the ruminant or a biocompatible and compound compatible delivery module well known to those skilled in the art. Such well known dosage forms are designed such that the active ingredients are slowly released over a period of several days to several weeks. The implant is designed to deliver from about 0.15-8.5 μg/kg of body weight/day, preferably from about 1.5-5.0 μg/kg of body weight/day.

When given by injection, the compounds of the present invention can be administered to the ruminants with any biocompatible and compound compatible carrier such as various vehicles, adjuvants, additives, and diluents to achieve a composition usable as a dosage form. The compounds of the present invention are added to the carrier in amounts sufficient to supply from about 0.01-0.5 mg/kg of body weight to the ruminant when injected. Preferably, the compounds of the present invention are added to an oil vehicle in amounts sufficient to supply from about 0.1-0.3 mg/kg of body weight.

Aqueous vehicles such as water having no nonvolatile pyrogens, sterile water, and bacteriostatic water are also suitable to form injectable compound compositions. In addition, several other aqueous vehicles can be used. These include isotonic injection compositions that can be sterilized such as Ringer's, dextrose, dextrose and sodium chloride, and lactated Ringer's. Addition of water-miscible solvents, such as methanol, ethanol, or propylene glycol generally increases solubility of the compounds in these vehicles.

Nonaqueous vehicles such as cottonseed oil, sesame oil, or peanut oil and esters such as isopropyl myristate may also be used as solvent systems for compound compositions. Additionally various additives which enhance the stability, sterility, and isotonicity of the composition including antimicrobial preservatives, antioxidants, chelating agents, and buffers can be added. Any vehicle, diluent, or additive used would, however, have to be compatible with the compounds of the present invention.

The compounds according to the present invention can be administered orally to the ruminant. For example, the compounds of the present invention can be blended with ordinary feed compositions in amounts sufficient to promote growth. When the compounds of the present invention are to be administered in feeds, a ruminant feed composition may be prepared containing the usual nutritionally-balanced feed containing quantities of carbohydrates, proteins, vitamins and minerals, together with the compounds in accordance with the present invention. Some of the usual dietary elements included in ruminant feed compositions are grains, such as ground grain and grain byproducts, animal protein substances, such as those found in fish meal and meat scraps, vegetable proteins, like soybean oil meal or peanut oil meal; vitamins and vitamin-containing materials, e.g., vitamin A and D mixtures, riboflavin supplements and other vitamin B complex members; and bone meal and limestone to provide minerals. A type of conventional feed material for use with cattle includes alfalfa hay and ground corncobs together with supplementary vitamins and vitamin-containing substances if desired. The compounds according to the present invention are admixed with the feed in amounts sufficient to supply from about 0.01-0.50 mg/kg body weight, typically 0.4-20 grams/ton of feed, to the ruminant.

The compounds of the present invention are useful as growth promotants in ruminants. In addition, the compounds can be used in post-menopausal replacement therapy.

Although not wishing to be bound by theory, it is believed that the carbamate derivatives of the present invention are cleaved in vivo to form the corresponding alcohol. For example, carbamates of zearalanol are hydrolyzed in vivo to form zearalanol. The parent compound, zearalanol in the example, effects the desired growth promotion or other effect. A significant advantage is achieved by administering the derivative instead of parent compound; the derivative is not cleared by the body as fast as is the parent compound thus allowing the growth promoting effect to be extended over a longer period. This increases the amount of growth promotion produced by a given amount of compound, reduces the amount of compound that must be administered to achieve the desired growth promotion, and decreases the number of dosages that must be administered in a given time.

The invention having been generally described, the following examples are given as particular embodiments of the invention and to demonstrate the practice and advantages thereof. U.S. Pat. Nos. 3,196,019, 3,239,345, and 3,239,348, incorporated herein by reference, disclose methods for producing zearalenone, zearalenol, zearalanol, and various esters and other derivatives of these compounds. These compounds and their derivatives are used to produce the compounds of the present invention. It is understood that the examples are given by way of illustration and are not intended to limit the specification or the claims to follow in any manner. In particular, the specification and claims as written are intended to include all isomers of the compounds and the alkyl groups are intended to include linear and branched chains.

EXAMPLE 1 Preparation of 6'-Zearalanol N,N-Dimethylcarbamate

A mixture of 250 ml of xylene, 6.0 g of zearalanol, and 6.0 g of dimethylcarbamyl chloride was refluxed for 22.5 hours. The reaction mixture was left one day to evaporate, then filtered and concentrated to 100 ml. This concentrate was left 48 h to evaporate, then filtered to give 2.6 g which was then crystallized from 25 ml of ethyl acetate to give 1.7 g, M.P. 155°-158° C. Analysis--calculated for C₂₁ H₃₁ NO₆ (393.47): C- 64.10%, H-7.94%, N-3.56%. Found: C-63.85%, H-7.75%, N-3.42%.

EXAMPLE 2 Preparation of 6'-Zearalanol N,N-Diethylcarbamate

A solution of 6.0 g of zearalanol and 5.0 g of diethylcarbamyl chloride in 250 ml of xylene was refluxed for 12 h. The reaction mixture was left for 72 h to evaporate. Filtration gave 0.5 g, M.P. 190°-192.5° C. after the xylene had been washed off with 2-propanol Analysis--calculated for C₂₃ H₃₅ NO₆ (421.52): C-65.53%, H-8.37%, N-₃.32 %; Found: C-65.29%, H-8.33%, N-3.47%.

EXAMPLE 3 Preparation of 6'-Zearalanol N,N-3-Oxapentamethylenecarbamate

To 15 ml of morpholine was added 5.0 g of 2,2,2-trichloroethyl 2,4-diacetyl-6'-zearalanol carbonate. The temperature rose to 40° C. and the 2,2,2-trichloroethyl 2,4-diacetyl-6'-zearalanol carbonate went into solution. After 72 h the solution was mixed with 350 ml of water and the mixture was acidified with dilute hydrochloric acid. Crystals formed. Filtered to give 3.1 g, M.P. 151°-154° C. The crystals were recrystallized from 25 ml of ethyl acetate to give 1.8 g, M.P. 154°-156° C. Analysis--calculated for C₂₃ H₃₃ NO₇ (435.50); C-63.43%, H-7.64%, N-3.22%, 0-25.72%. Found: C-63.94%, H-7.77%, N-3.15%, 0-25.44%. The molecular weight was confirmed by mass spectrometry.

EXAMPLE 4 Preparation of 6'-Zearalanol N,N-Pentamethylenecarbamate

To 15 ml of piperidine was added 5.0 g of 2,2,2-trichloroethyl 2,4-diacetyl-6'-zearalanol carbonate. The mixture rapidly became one phase, and the temperature rose to 39° C. After three days the solution was mixed with 350 ml of water, and acidified with dilute hydrochloric acid. The white solid which separated was recrystallized from 45 ml of ethyl acetate. This gave 2.3 g, M.P. 175°-177° C. It was recrystallized again from 35 ml of ethyl acetate to give 1.8 g, M.P. 175°-177° C. Analysis--calculated for C₂₆ H₃₅ NO₆ (433.53): C-66.44%, H-8.14%, N-3.23%, O-22.14%. Found: C-66.30%, H-8.21%, N-3.22%, O-22.42%. The molecular weight was confirmed by mass spectrometry.

EXAMPLE 5 Preparation of the Cyclohexylamine Salt of 6'-Zearalanol N-Cyclohexylcarbmate

To 15 ml of cyclohexylamine was added 5.0 g of 2,2,2-trichloroethyl 2,4-diacetyl-6'-zearalanol carbonate. The 2,2,2-trichloroethyl 2,4-diacetyl-6'-zearalanol carbonate dissolved and the temperature rose to 44° C. After two days the solution was mixed with 350 ml of water and just acidified with dilute hydrochloric acid. The 4.4 g of crude crystals recovered were recrystallized from 100 ml of ethyl acetate (not enough) to give 1.9 g of crystalline product melting at 117°-120° C. The experiment was repeated and the two products mixed and recrystallized to give crystals melting at 118°-120.5° C. Analysis--calculated for C₃₁ H₅₀ N₂ O₆ (546.72): C-68.10%, H-9.22%, N-5.12%, O-17.56%. Found: C-68.03%, H-9.30%, N-4.99%, O-17.72%. The identity was consistent with the mass spectrogram.

EXAMPLE 6

The uterotropic activity screening test was conducted in young adult female mice (CF1 strain) weighing 19-24 g each, purchased from Engle's Laboratory Animals, Farmersburg, Ind. The test mice were ovariectomized and held for two weeks to allow for depletion of natural estrogens.

The tests were conducted by administering to groups of mice, a selected total dose of test material divided into three consecutive days. Positive and negative control groups were also tested for comparison. On the fourth day, all mice were sacrificed, body weights were made and recorded, the uterus of each mouse removed, weighed and recorded. Average body and uterine weights were calculated. For comparison, the percent uterine weight to body weight was determined.

Uterotropic activity was indicated when the percent uterine weight to body weight in a test group was greater than that of a negative control group. Uterotropic activity of a test material may then be compared to that of a known estrogenic material. The results are shown in Table 1.

                  TABLE 1                                                          ______________________________________                                         6'-Carbamates of Zearalanol                                                    R.sub.1                                                                             R.sub.2                                                                               R           M.P.      IP.sup.1                                                                            Oral.sup.1                              ______________________________________                                         H    H      N(CH.sub.3).sub.2                                                                          155-158   0.7  0                                       H    H      N(C.sub.2 H.sub.5).sub.2                                                                     190-192.5                                                                              0    0                                       H    H      Morpholinium                                                                               154-156   0.8  0                                       H    H      Piperidinium                                                                               175-177   0.2  0                                       ______________________________________                                          .sup.1 Approx. mouse uterotropic value relative to zearalanol obtained by      dividing the increase in uterine weight by the increase from zearalanol        both at 100 μ g total dose.                                            

I claim:
 1. A method for promoting growth in a ruminant comprising the step of:administering to said ruminant a growth promoting amount of a compound having the formula: ##STR4## wherein R₁ and R₂, which may be the same or different, are H, X, or COX, where X is an alkyl group having from 1-6 carbon atoms; and R is NH--Y, where Y is an alkyl group having from 1-6 carbon atoms.
 2. The method of claim 1 wherein R₁ and R₂ are H, CH₃, or COCH₃ ; and R is N(CH₃)₂ or N(C₂ H₅)₂.
 3. The method of claim 1 wherein said compound is administered in an amount from about 0.01-0.50 mg/kg of body weight.
 4. The method of claim 1 wherein said compound is administered orally, said oral method selected from the group consisting of administering said compound to said ruminants in tablets, suspensions, solutions, emulsions, capsules, powders, syrups, boluses, and feed compositions.
 5. The method of claim 1 wherein said compound is administered in a feed composition, said feed composition further comprising:a nutritionally balanced feed; and a growth promoting amount of at least one of said compound admixed with said feed.
 6. The method of claim 1 wherein said compound is administered by injecting a composition, said composition further comprising:a biocompatible and compound compatible vehicle; and a growth promoting amount of said compound admixed with said composition.
 7. The method of claim 6 wherein said vehicle is an oil vehicle.
 8. The method of claim 1 wherein said compound is administered using an implant, said implant further comprising:a biocompatible and compound compatible implant material; and a growth promoting amount of said compound admixed with said implant material. 